EODPP has been working with the National Cancer Institute (NCI) to obtain the SEER/Medicare Linkage project database for use in a number of investigations in oral cancer. The Linkage Project is a collaborative effort by the NCI and the Health Care Financing Administration (HCFA) to link the NCI's Surveillance, Epidemiology, and End Results (SEER) Program data base, which contains information on cancer cases diagnosed and reported in nine geographically distinct population-based tumor registries, and HCFA's Medicare statistical system (MSS), which contains extensive billing information for the health care of the disabled and more than 95 percent of the elderly. Initial work has begun at NIDR on developing an analysis plan for oral cavity and pharyngeal cancer utilizing this linked data base. The objectives of this study are to: 1) identify regional (SEER) variations in the choice of first-course of cancer directed therapy among individuals 65 years of age and over with oral cavity and pharyngeal cancer, by site of cancer; 2) add to the information currently available concerning the effectiveness of alternative therapies used to manage oral cavity and pharyngeal cancer among the elderly population; and 3) estimate the lifetime costs associated with oral cavity and pharyngeal cancer. For the years 1984 to 1989, 7,014 incident cases of oral cavity and pharyngeal cancer are contained in the data base, representing over 32,400 person-years.